Certain perishable liquid products such as orange juice and other fresh juices must be maintained during transportation and storage at temperatures substantially below ambient temperature in order to prevent spoilage and to satisfy applicable governmental regulations. With respect to fresh orange juice, for example, it is typically required that the product be maintained at all times at or below a maximum temperature of 38 degrees Fahrenheit. Above that temperature, orange juice risks fermentation.
While it is possible to utilize vehicles with on-board cooling systems to satisfy temperature requirements for perishable liquid products, the cost and maintenance of such systems on liquid tankers ordinarily makes this an economically unattractive alternative. As a result, use of refrigerated vehicles for such shipments is not common. Conventionally, juices to be stored and transported via uncooled tanker trucks are subjected to chilling by mechanical refrigeration such as ammonia and glycol chillers prior to loading at the point of origin. While this may prove effective if the length of travel is short, or the climate through which the shipment is to travel is rather cool, such techniques have not proven to be universally satisfactory. These conventional cooling procedures at the point of origin are at times supplemented by adding quantities of ice or mechanically frozen juice to the uncooled tanker along with the liquid juice. This can improve the success rate for shipment, but at a cost of considerable time and labor at the point of origin, and with uncertainty as to the actual level of heat load protection achieved.